Energy-induced dual curable compositions

ABSTRACT

An energy polymerizable composition comprises at least one ethylenically-unsaturated monomer, one of polyurethane precursors, and at least one epoxy monomer, and a curing agent comprising an organometallic compound, and an onium salt.

This is a division of application Ser. No. 07/090,694 filed Aug. 28,1987, now U.S. Pat. No. 4,950,956.

FIELD OF THE INVENTION

This invention relates to an energy-polymerizable composition comprisingan ethylenically-unsaturated monomer and either polyurethane precursorsor an epoxy monomer, and as curing agent a combination of anorganometallic compound and an oxidizing agent, and a method therefor.In a further aspect, cured articles comprising the composition of theinvention are disclosed. The compositions are useful, for example, asprotective coatings, binders for magnetic media or abrasives, adhesives,and in graphic arts applications.

BACKGROUND OF THE INVENTION

Various polymeric coatings and articles are produced in processesinvolving the use/of organic solvents. There is an intense effort by lawmakers, researchers, and industry to promote high and 100% solidsformulations to reduce or eliminate the use of such solvents and theattendant costs and environmental contamination. These processes requirea latent catalyst or latent reaction promoter which can be activated ina controlled fashion.

Thermal curing of polyurethane precursors using reaction promoters suchas tin salts and tertiaryamines is known in the art. Curing ofpolymerizable mixtures of polyisocyanates with polyols (referred to aspolyurethane precursors) using thermally latent catalysts is known inthe art (see for example U.S. Pat. Nos. 4,521,545, and 4,582,861).

Photocuring of urethane (meth)acrylates is well known (see T. A.Speckhard, K. K. S. Hwang, S. B. Lin, S. Y. Tsay, M. Koshiba, Y. S.Ding, S. L. Cooper J. Appl. Polymer Science, 1985, 30, 647-666; C.Bluestein Polym.-Plast. Technol. Eng. 1981, 17 83-93), and photocuringof polyurethane precursors using diazonium salts, tertiaryamineprecursors, and organotin compounds is also known (see U.S. Pat. Nos.4,544,466, 4,549,945, and EP 28,696, Derwent abstract). All of thesemethods suffer from one or more of the following disadvantages:sensitivity to oxygen, requirement of ultraviolet and/or high intensitylight, the need for modified resins, loss or dilution of urethaneproperties, low activity, poor solubility, and poor potlife.

The dual curing of acrylate/urethane precursor mixtures is known butthese curing methods are not entirely photoactivated nor are any methodsknown that provide for the simultaneous curing of the urethaneprecursors and acrylates (see U.S. Pat. No. 4,342,793 and Roesler,Modern Paint and Coatings, April, 1986, pages 46-55).

The prior art discloses processes for the polymerization of epoxymaterials. It is further known that a metallocene, such as ferrocene,can be used as a curing accelerator for epoxy materials (U.S. Pat. No.3,705,129). U.S. Pat. Nos. 3,709,861, 3,714,006, 3,867,354 and 4,237,242relate to the use of transition metal complexes in the reaction betweenpolyepoxides and polyfunctional curing additives, but they do not teachthe polymerization of epoxide group-containing compositions notcontaining a curing additive. The polymerization of epoxidegroup-containing materials is also known. Among such processes are thosein which the polymerization catalyst is a radiation-sensitive onium saltof a Lewis acid (e.g. diazonium salts as is described in U.S. Pat. No.3,794,576 and U.S. Pat. No. 4,080,274; halonium salts as is disclosed inU.S. Pat. No. 4,026,705; and the onium salts of Group VIA elements,particularly the sulfonium salts, as are disclosed in U.S. Pat. No.4,058,400), or a dicarbonyl chelate compound of a Group IIIA-VA elementas is disclosed in U.S. Pat. No. 4,086,091. These compositions arelimited to ultraviolet radiation for polymerization. Furthermore, thedicarbonyl chelates are moisture sensitive.

U.S. Pat. No. 4,216,288 teaches the thermal curing of cationicallypolymerizable compositions using onium salts and reducing agents.

Radiation dual curable compositions containing ethylenically unsaturatedmonomers and epoxy monomers have been described in U.S. Pat. Nos.4,156,035, 4,227,978, and 4,623,676. These compositions include oniumsalts combined with organic compounds as the curing agent, but do notcontain any organometallic compounds.

Energy polymerizable compositions comprising ionic salts oforganometallic complex cations and cationically sensitive materials andthe curing thereof has been taught (see European Patent Nos. 109,851,1984; 094,915, 1983, Derwent abstract; and 094, 415, 1983, Derwentabstract).

Neutral organometallic compounds have been used in combination withneutral halogenated compounds for the photocuring.ofethylenically-unsaturated monomers. (G. Smets, Pure G. Appl. Chem., 53,611,615 (1981); H. M. Wagner, M. D. Purbrick, J. Photograph Science, 29,230-235.

The use of certain photosensitizers with onium salts for initiation ofpolymerization of ethylenically unsaturated monomers is also well knownin the art. This technique has found applications in printing,duplication, copying, and other imaging systems (see J. Kosar in LightSensitive Systems: Chemistry and Application of Nonsilver HalidePhotographic Processes, Wiley, New York, 1965, pp 58-193). Aryliodoniumsalts have been previously described for use as photoinitiators inaddition-polymerizable compositions. (See U.S. Pat. Nos. 3,729,313,3,741,769, 3,808,006, 4,228,232, 4,250,053 and 4,428,807; H. J. Timpeand H. Baumann, Wiss Z. Tech. Hochsch. Leuna-Merseburg, 26, 439 (1984);H. Baumann, B. Strehmel, H. J. Timpe and U. Lammel, J. Prakt. Chem., 326(3), 415 (1984); and H. Baumann, U. Oertel and H. J. Timpe, Euro. Polym.J., 22 (4), 313 (Apr. 3, 1986).

SUMMARY OF THE INVENTION

Briefly, the present invention provides an energy polymerizablecomposition comprising an ethylenically-unsaturated monomer and eitherpolyurethane precursors or an epoxy monomer, and as curing agent acombination of a organometallic compound and an onium salt. Thecompositions are useful as protective and decorative coatings, inks,adhesives, binders for magnetic media or abrasives, in restorative andsealant applications, and in imaging applications.

It is believed not known in the art that latent, energy induced,simultaneous, preferably solventless, dual curing ofethylenically-unsaturated monomers, in combination with eitherpolyurethane precursors or epoxy monomers, can be achieved by using ascuring agent a combination of an organometallic compound and an oniumsalt oxidizing agent.

Advantages of compositions of the present invention when utilized in100% reactive coating compositions include:

An industrial process innovation is disclosed that will reduce,minimize, or eliminate the generation of industrial solvent waste whilereducing energy consumption.

Radiation processing, particularly utilizing electron beam andphotogenerated catalysts, has potential capability for penetrating andpolymerizing thick and pigmented coatings.

More readily available monomers can be used in place of functionalizedoligomers (used in the prior art) thereby resulting in lower viscositymonomer solutions which are easier to coat than more viscous oligomersolutions.

Expanding the scope of curable monomers to includepolyisocyanates/polyols and epoxides allows increased flexibility indesigning coatings with specific properties.

In this application:

"dual curing" means the simultaneous energy-induced curing ofethylenically-unsaturated monomers in combination with one ofpolyurethane precursors and epoxy monomers;

"energy-induced curing" means curing by means of electromagneticradiation (ultraviolet and visible) accelerated particles (includingelectron beam), and thermal (infrared and heat) means;

"ethylenically unsaturated monomer" means those monomers that polymerizeby a free-radical mechanism;

"catalytically-effective amount" means a quantity sufficient to effectpolymerization of the curable composition to a polymerized product atleast to a degree to cause an increase in the viscosity of thecomposition;

"organometallic compound" means a chemical substance in which at leastone carbon atom of an organic group is bonded to a metal atom ("BasicInorganic Chemistry", F. A. Cotton, G. Wilkinson, Wiley, New York, 1976,p 497);

"polyurethane precursors" means a mixture of one or monomers of the typeincluding diisocyanates and polyisocyanates, and one or more monomers ofthe type including diols and polyols. Compounds bearing at least twoisocyanate-reactive hydrogen atoms may be substituted for diols andpolyols; the ratio of isocyanate groups to isocyanate-reactive hydrogenatoms is 1:2 to 2:1;

"polymerizable mixture" means a mixture where the ratio of(ethylenically-unsaturated compounds) : (polyurethane precursors orepoxy compounds) is 1:99 to 9:1;

"bridging ligand" means a ligand that bonds to two or more metals in thepresence or absence of metal-metal bonds;

"polyisocyanate" means an aliphatic or aromatic isocyanate having 2 ormore isocyanate groups;

"polyol" means an aliphatic or aromatic compound containing 2 or morehydroxyl groups; and

"onium salt" means salts of cationic compounds such as diazonium,halonium, and hypervalent Group VIA elements;

An energy polymerizable mixture comprising an ethylenically unsaturatedmonomer and either polyurethane precursors or an epoxy compound and ascuring agent an organometallic compound and an onium salt is disclosedin assignee's copending patent application U.S. Ser. No. 07/090,791,filed the same date as this application, now U.S. Pat. No. 4,952,612.

DETAILED DESCRIPTION OF THE INVENTION

More specifically, in a preferred embodiment this invention describes anenergy polymerizable composition comprising in the range of 99 to 1weight percent an ethylenically-unsaturated monomer and 1 to 99 weightpercent of either polyurethane precursors or an epoxy monomer and abicomponent curing agent therefor, the curing agent comprising

1) an organometallic compound having the structure

    L.sup.1 L.sup.2 L.sup.3 M

wherein

L¹ represents none, or 1 to 12 ligands contributing pi-electrons thatcan be the same or different ligand selected from substituted andunsubstituted acyclic and cyclic unsaturated compounds and groups andsubstituted and unsubstituted carbocyclic aromatic and heterocyclicaromatic compounds, each capable of contributing 2 to 12 pi-electrons tothe valence shell of M;

L² represents none, or 1 to 24 ligands that can be the same or differentcontributing an even number of sigma-electrons selected from mono-, di-,and tri-dentate ligands, each donating 2, 4, or 6 sigma-electrons to thevalence shell of M;

L³ represents none, or 1 to 12 ligands that can be the same ordifferent, each contributing no than one sigma electron each to thevalence shell of each M;

M represents 1 to 4 of the same or different metal atoms selected fromthe elements of Periodic Groups IVB, VB, VIB, VIIB, and VIII (commonlyreferred to as transition metals);

with the proviso that said organometallic compounds contains at leastone of a metal-metal sigma bond and L³ ; and with the proviso that L¹,L², L³, and M are chosen so as to achieve a stable configuration, and

2) an onium salt oxidizing agent having the structure II

    AX                                                         II

wherein

A is an organic cation selected from those described in U.S. Pat. Nos.3,708,296, 3,729,313, 3,741,769, 3,794,576, 3,808,006, 4,026,705,4,058,401, 4,069,055, 4,101,513, 4,216,288, 4,394,403, and 4,623,676,all incorporated herein by reference, preferably selected fromdiazonium, iodonium, and sulfonium cations, while more preferably A isselected from diphenyliodonium, triphenylsulfonium and phenylthiophenyldiphenylsulfonium; and

X is an anion, the counterion of the onium salts including those inwhich X is an organic sulfonate, or halogenated metal or metalloid, suchas CH₃ SO₃ ⁻, CF₃ SO₃ ⁻, C₆ H₅ SO₃ ⁻, p-toluenesulfonate,p-chlorobenzenesulfonate and related isomers and the like, and

those in which X has the formula DZr, wherein D is a metal from GroupsIB to VIIIB or a metal or metalloid from Groups IIIA to VA of thePeriodic Chart of Elements, Z is a halogen atom, and r is an integerhaving a value of 1 to 6. Preferably, the metals are copper, zinc,titanium, vanadium, chromium, manganese, iron, cobalt, or nickel and themetalloids preferably are boron, aluminum, antimony, tin, arsenic, andphosphorous. Preferably, the halogen, Z, is chlorine or fluorine.Illustrative of suitable anions are BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻, SbF₆ ⁻, FeCl₄⁻, SnCl₅ ⁻, SbF₅ ⁻, AlF₆ ⁻, GaCl₄ ⁻, InF₄ ⁻, TiF₆ ⁻, etc. Preferably,the anions ar CV₃ SO₃ ⁻, BF₄ ⁻, PF₆ ⁻, SbF₆ ⁻, SbF₅ OH⁻, AsF₆ ⁻ andSbCl₆ ⁻.

The curing agent can be present in the range of 0.1 to 20, preferably0.1 to 10 weight percent of the total composition. The ratio oforganometallic compound to onium salt is in the range of 10:1 to 1:10 byweight, preferably 1 to 1:5 by weight.

The present invention also provides a process for the polymerization ofethylenically-unsaturated monomers in combination with one ofpolyurethane precursors and epoxy monomers comprising the steps of:

(a) providing a mixture of at least one ethylenically-unsaturatedmonomers and either polyurethane precursors or an epoxy compound,

(b) adding to said mixture a combination of a catalytically effectiveamount of a curing agent comprising an organometallic compound and anonium salt (and all permutations of the order of mixing theaforementioned components), thereby forming a polymerizable mixture, and

(c) allowing the mixture to polymerize or adding energy to the mixtureto effect polymerization.

In a further aspect, there is also provided a method for preparingcoated articles containing the cured composition of the inventioncomprising the steps of:

(a) providing a substrate,

(b) coating an energy polymerizable mixture as described above to thesubstrate by methods known in the art, such as bar, knife, reverse roll,knurled roll, or spin coatings, or by dipping, spraying, brushing, andthe like, with or without a coating solvent, and

(c) applying energy (after evaporation of solvent, if present) to thearticle to cause the polymerization of the coating.

In a still further aspect, there are also provided shaped articlescomprising the polymerizable mixture of the invention. The articles canbe provided, for example, by techniques such as molding, injectionmolding, casting, and extrusion. Applying energy to the mixture causespolymerization and provides the cured shaped article.

It is not preferred, but it may be desirable to add solvent tosolubilize components and aid in processing. Solvent, preferably anorganic solvent, in an amount up to weight percent, but preferably inthe range of 0 to 90 weight percent, most preferably in the range of 0to 75 weight percent, of the polymerizable composition can be used.

There are restrictions on the total sum of electrons donated by theligands, L¹, L², L³ of formula I and the valence electrons possessed bythe metal. For most organometallic compounds not involvingintramolecular metal-metal bonding, this sum is governed by the"eighteen electron rule" [see J. Chem. Ed., 46, 811 (1969)]. This ruleis sometimes called the "nine orbital rule", "the effective numberrule", or the "rare gas rule". This rule states that the most stableorganometallic compounds tend to be those compounds in which the sum ofthe electrons donated by the ligands and the metal is eighteen. Thoseskilled in the art, however, know that there are exceptions to this ruleand that organometallic compounds having a sum of 16, 17, 19, and 20electrons are also known. Therefore, organometallic compounds notincluding intramolecular metal-metal bonding are described by formula I,in which complexed metals having a total sum of 16, 17, 18, 19, or 20electrons in the valence shell are included within the scope of theinvention.

For compounds described in formula I in which intramolecular metal-metalbonding exists serious departure from the "eighteen electron rule" canoccur. It has been proposed [J. Amer. Chem. Soc. 100, 5305 (1978)] thatthe departure from the "eighteen electron rule" in these transitionmetal compounds is due to the metal-metal interactions destabilizing themetal p orbitals to an extent to cause them to be unavailable for ligandbonding. Hence, rather than count electrons around each metal separatelyin a metal cluster, cluster valence electrons (CVE) are counted. Adinuclear compound, is seen to have 34 CVEs, a trinuclear compound, 48CVEs, and a tetranuclear compound, having tetrahedron, butterfly, andsqure planar geometry is seen to have 60, 62, or 64 CVEs, respectively.Those skilled in the art, however, know that there are exceptions tothis electron counting method and that organometallic complex clustercompounds having a sum of 42, 44, 46, 50 CVEs for a trinuclear compoundand 58 CVEs for a tetranuclear compound are also known. Therefore, di,tri, or tetranuclear organometallic compounds are described by formula Iin which the complexed metal cluster, MM, MMM, or MMMM has a total. sumof 34; 42, 44, 46, 48, 50; or 58, 60, 62, 64 CVEs in the valence shell,respectively, and are included within the scope of this invention.

Illustrative examples of organometallic compounds according to formula Iinclude:

[CpFe(CO)₂ ]₂ :

Mn₂ (CO)₁₀

[CpMo(CO)₃ ]₂

[CpW(CO)₃ ]₂

Re₂ (CO)₁₀

Co₄ (CO)₁₂

Co₂ (CO)₈

CpFe(CO)₂ SnPh₃

CpFe(CO)₂ GePh₃

[CpFe(CO)₂ ]₂ SnPh₂

CpMo(CO)₃ SnPh₃

(CO)₅ MnSnPh₃

[(CO)₅ Mn]₂ SnPh₂

CpFe(CO)₂ PbPh₃

(CO)₅ MnPbPh₃

(CO)₅ ReSnPh₃

CpPtMe₃

CpW(CO)₃ Me

Cp(CO)₃ W-Mo(CO)₃ Cp

Cp(CO)₃ Mo-Mn(CO)₅

Cp(CO)₃ Mo-Re(CO)₅

Cp(CO)₃ W-Mn(CO)₅

Cp(CO)₃ W-Re(CO)₅

Cp(CO)₃ Mo-Co(CO)₄

Cp(CO)₃ W-Co(CO)₄

Cp(CO)₃ Mo-Fe(CO)₂ Cp

(CO)₅ Mn-Fe(CO)₂ Cp

Cp(CO)₃ W-Fe(CO)₂ Cp

[CpMo(CO)₂ PPh₃ ]₂

Mn₂ (CO)₉ PPh₃

Mn₂ (CO)₈ (PPh₃)₂

(CO)₅ Mn-Re(CO)₅

Mn₂ (CO)₈ (1,10-phenanthroline)

[CpFe(CO)₂ ]₄ Si

Re₂ (CO)₈ (1,10-phenanthroline)

Re₂ (CO)₈ (2,2'-biquinoline)

Fe₃ (CO)₁₂

Ru₃ (CO)₁₂

Os₃ (CO)₁₂

Ru₃ (CO)₁₁ PPh₃

Ru₃ (CO)₁₀ (Ph₂ P--CH₂ CH₂ --PPh₂)

Fe₂ Ru(CO)₁₂

Ir₄ (CO)₁₂

[CpNi(CO)]₂

CpFe(CO)₂ CH₂ Ph

CpFe(CO)₂ (COPh)

CpFe(CO)₂ (SiPh₃)

[Cp* Fe(CO)₂ ]₂

Cp(CO)₂ Fe--Fe(CO)(PPh₃)Cp

(MeCp)PtMe₃

(Me₃ SiCp)PtMe₃

Cp(CO)₃ Mo--Mo(CO)₂ (PPh₃)Cp

wherein

Me is methyl

Ph is phenyl

Cp is eta⁵ -cyclopentadienyl

Cp* is eta⁵ -pentamethylcyclopentadienyl

A wide variety of monomers can be energy

using the curing agent of the invention. Suitable compounds containingat least one ethylenically-unsaturated double bond, can be monomersand/or oligomers such as (meth)acrylates, (meth)acrylamides, and vinylcompounds, and are capable of undergoing addition

Such monomers include mono-, di-, or poly- acrylates and methacrylatessuch as methyl acrylate, methyl methacrylate, ethyl acryate, isopropylmethacrylate, n-hexyl acrylate, stearyl acrylate, allyl acrylate,glycerol diacrylate, glycerol triacrylate, ethyleneglycol diacrylate,diethyleneglycol diacrylate, triethyleneglycol dimethacrylate,1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate,trimethylolpropane triacrylate, 1,2,4-butanetriol trimethylacrylate,1,4-cyclohexanediol diacrylate, pentaerythritol triacrylate,pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate,sorbitol hexacrylate,bis[1-(2-acryloxy)]-p-ethoxyphenyl-dimethylmethane,bis[1-(3-acryloxy-2-hydroxy)]-p-propoxyphenyl-dimethylmethane,tris-hydroxyethyl-isocyanurate trimethacrylate; the bis-acrylates andbis-methacrylates of polyethylene glycols of molecular weight 200-500,copolymerizable mixtures of acrylated monomers such as those of U.S.Pat. No. 4,652,274, and acrylated oligomers such as those of U.S. Pat.No. 4,642,126; unsaturated amides such as acrylami methylenebis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylenebis-acrylamide, diethylene triamine tris-acrylamide andbeta-methacrylaminoethyl methacrylate; and vinyl compounds such asstyrene, divinylbenzene diallyl phthalate, divinyl succinate, divinyladipate, divinyl phthalate, and vinyl azlactones as disclosed in U.S.Pat. No. 4,304,705. Mixtures of two or more monomers can be used ifdesired.

The polyisocyanate component of the polyurethane precursors that can becured or polymerized in the dual curing systems of the present inventionmay be any aliphatic, cycloaliphatic, araliphatic, aromatic, orheterocyclic polyisocyanate, or any combination of such polyisocyanates.Particularly suitable polyisocyanates correspond to the formula

    Q(NCO).sub.P                                               III

in which p is an integer 2 to 4, and Q represents an aliphatichydrocarbon di-, tri-, or tetra-radical containing from 2 to 100 carbonatoms, and zero to 50 heteroatoms, a cycloaliphatic hydrocarbon radicalcontaining from 4 to 100 carbon atoms and zero to 50 heteroatoms, anaromatic hydrocarbon radical or heterocyclic aromatic radical containingfrom 5 to 15 carbon atoms and zero to 10 heteroatoms, or an araliphatichydrocarbon radical containing from 8 to 100 carbon atoms and zero to 50heteroatoms. The heteroatoms that can be present in Q includenon-peroxidic oxygen, sulfur, non-amino nitrogen, halogen, silicon, andnon-phosphino phosphorus.

Examples of polyisocyanates are as follows: ethylene diisocyanate,1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate,trimethyl hexamethylene diisocyanate, 1,12-dodecane diisocyanate,cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate andmixtures of these isomers,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (see GermanAuslegeschrift No. 1,202,785, U.S. Pat. No. 3,401,190), 2,4- and2,6-hexahydrotolylene diisocyanate and mixtures of these isomers,hexahydro-1,3- and/or -1,4- phenylene diisocyanate, perhydro-2,4'-and/or -4,4,- diphenylmethane diisocyanate, 1,3- and 1,4-phenylenediisocyanate, 2,4- and 2,6-tolylene diisocyanate and mixtures of theseisomers, diphenylmethane-2,4'- and/or - 4,4'-diisocyanate,naphthylene-1,5-diisocyanate, and the reaction products of fourequivalents of the aforementioned isocyanate-containing compounds withcompounds containing two isocyanate-reactive groups.

According to the present invention, it is also possible for example, touse triphenyl methane-4,4',4"-triisocyanate, polyphenyl polymethylenepolyisocyanates described in British Patent Nos. 874,430 and 848,671, m-and p-isocyanatophenyl sulphonyl isocyanates according to U.S. Pat. No.3,454,606, perchlorinated aryl polyisocyanates of the type described,for example, in German Auslegeschrift No. 1,157,601 (U.S. Pat. No.3,277,138), polyisocyanates containing carbodiimide groups of the typedescribed in U.S. Pat. No. 3,152,162 and in German OffenlegungsschriftNos. 2,504,400, 2,537,685 and 2,552,350, norbornane diisocyanatesaccording to U.S. Pat. No. 3,492,330, polyisocyanates containingallophanate groups of the type described, for example, in British PatentNo. 994,890, in Belgian Pat. No. 761,626 and in Dutch Patent ApplicationNo. 7,102,524, polyisocyanates containing isocyanurate groups of thetype described, for example in U.S. Pat. No. 3,001,973, in German PatentNos. 1,022,789, 1,222,067 and 1,027,394 and German OffenlegungsschriftNos. 1,929,034 and 2,004,048, polyisocyanates containing urethane groupsof the type described, for example, in Belgian Patent No. 752,261 or inU.S. Pat. Nos. 3,394,164 and 3,644,457, polyisocyanates containingacrylated urea groups according to German Patent No. 1,230,778,polyisocyanates containing biuret groups of the type described, forexample, in U.S. Pat. Nos. 3,124,605, 3,201,372 and 3,124,605 and inBritish Patent No. 889.050, polyisocyanates produced by telomerizationreactions of the type described for example in U.S. Pat. No. 3,654,106,polyisocyanates containing ester groups of the type described, forexample, in British Patent Nos. 965,474 and 1,072,956, in U.S. Pat. No.3,567,763 and in German Patent No. 1,231,688, reaction products of theabove-mentioned diisocyanates with acetals according to German Patent1,072,385 and polyisocyanates containing polymeric fatty acid estersaccording to U.S. Pat. No. 3,455,883.

It is also possible to use distillation residues having isocyanategroups obtained in the commercial production of isocyanates, optionallyin solution in one or more of the above-mentioned polyisocyanates. It isalso possible to use any mixtures of the above-mentionedpolyisocyanates.

Preferred polyisocyanates are hexamethylene diisocyanate, itsisocyanurate and its biuret; 4,4'-methylene bis(cyclohexylisocyanate);1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophoronediisocyanate); the tolylene diisocyanates and their isocyanurates; themixed isocyanurate of tolylene diisocyanate and hexamethylenediisocyanate; the reaction product of 1 mol of trimethylol propane and 3mols of tolylene diisocyanate and also crude diphenyl methanediisocyanate.

Suitable compounds containing at least 2 isocyanate-reactive hydrogenatoms can be high or low molecular weight compounds, having a weightaverage molecular weight, generally from about 50 to 50,000. In additionto compounds containing amino groups, thiol groups or carboxyl groups,are, preferably, compounds containing hydroxyl groups, particularlycompounds containing from about 2 to 50 hydroxyl groups and above all,compounds having a weight average molecular weight of from about 500 to25000, preferably from about 700 to 2000, for example, polyesters,polyethers, polythioethers, polyacetals, polycarbonates,poly(meth)acrylates, and polyester amides, containing at least 2,generally from about 2 to 8, but preferably from about 2 to 4 hydroxylgroups, or even hydroxyl-containing prepolymers of these compounds and aless than equivalent quantity of polyisocyanate, of the type known forthe production of polyurethanes.

Representatives of the above-mentioned compounds used in accordance withthe present invention are described, for example, in High Polymers, Vol.XVI, "Polyurethanes, Chemistry and Technology", By Saunders and Frisch,Interscience Publishers, New York/London, and Vol. I, 1962, pages 32 to42 and pages 44 to 54 and Vol. II, 1964, pages 5-6 and 198-199, and inKunststoff-Handbuch, Vol. VII, Vieweg-Hochtlen, Carl- HanserVerlag,Munich, 1966, for example, on pages 45 to 71. It is, of course, possibleto use mixtures of the above-mentioned compounds containing at least twoisocyanate-reactive hydrogen atoms and having a molecular weight of fromabout 50 to 50,000 for example, mixtures of polyethers and polyesters.

In some cases, it is particularly advantageous to combine low-meltingand high-melting polyhydroxyl containing compounds with one another(German Offenlegungsschrift No. 2,706,297).

Low molecular weight compounds containing at least twoisocyanate-reactive hydrogen atoms (molecular weight from about 50 to400) suitable for use in accordance with the present invention arecompounds preferably containing hydroxyl groups and generally containingfrom about 2 to 8, preferably from about 2 to 4 isocyanate- reactivehydrogen atoms. It is also possible to use mixtures of differentcompounds containing at least two isocyanate-reactive hydrogen atoms andhaving a molecular weight in the range of from about 50 to 400. Examplesof such compounds are ethylene glycol, 1,2- and 1,3-propylene glycol,1,4- and 2,3-butylene glycol, 1,5-pentane diol, 1,6-hexane diol,1,8-octane diol, neopentyl glycol, 1,4-bis-hydroxymethyl cyclohexane,2-methyl-1,3-propane diol, dibromobutene diol (U.S. Pat. No. 3,723,392),glycerol, trimethylolpropane, 1,2,6-hexanetriol, trimethylolethane,pentaerythritol, quinitol, mannitol, sorbitol, diethylene glycol,triethylene glycol, tetraethylene glycol, higher polyethylene glycols,dipropylene glycol, higher polypropylene glycols, dibutylene glycol,higher polybutylene glycols, 4,4'-dihydroxy diphenyl propane anddihydroxy methyl hydroquinone.

Other polyols suitable for the purposes of the present invention are themixtures of hydroxy aldehydes and hydroxy ketones ("formose") or thepolyhydric alcohols obtained therefrom by reduction ("formitol") whichare formed in the autocondensation of formaldehyde hydrate in thepresence of metal compounds as catalysts and compounds capable ofenediol formation as co-catalysts (German Offenlegungsschrift Nos.2,639,084, 2,714,084, 2,714,104, 2,721,186, 2,738,154 and 2,738,512).Solutions of polyisocyanate polyaddition products, particularlysolutions of polyurethane ureas containing ionic groups and/or solutionsof polyhydrazodicarbonamides, in low molecular weight polyhydricalcohols may also be used as the polyol component in accordance with thepresent invention (German Offenlegungsschrift No. 2,638,759).

Many other compounds containing isocyanate-reactive hydrogen atoms andpolyisocyanates are useful in the present invention, and are obvious tothose skilled in the art of polyurethane science and technology.

Epoxy compounds that can be cured or polymerized in the dual systems bythe curing agents of this invention, using the latter in a catalyticallyeffective amount, are those known to undergo cationic polymerization andinclude 1,2-, 1,3-, and 1,4-cyclic ethers (also designated as 1,2-,1,3-, and 1,4-epoxides). The 1,2-cyclic ethers are preferred.

The cyclic ethers which can be polymerized in accordance with thisinvention include those described in "Ring-Opening Polymerizations",Vol. 2, by Frisch and Reegan, Marcel Dekker, Inc. (1969). Suitable1,2-cyclic ethers are the monomeric and polymeric types of epoxides.They can be aliphatic, cycloaliphatic, aromatic, or heterocyclic andwill typically have an epoxy equivalency of from 1 to 6, preferably 1 to3. Particularly useful are the aliphatic, cycloaliphatic, and glycidylether type 1,2-epoxides such as propylene oxide, epichlorohydrin,styrene oxide, vinylcyclohexene oxide, vinylcyclohexene dioxide,glycidol, butadiene oxide, glycidyl methacrylate, diglycidyl ether ofbisphenol A, cyclohexeneoxide,3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate,bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, dicyclopentadienedioxide, epoxidized polybutadiene, 1,4-butanediol diglycidyl ether,polyglycidyl ether of phenolformaldehyde resole or novolak resin,resorcinol diglycidyl ether, and epoxy silicones, e.g.,dimethylsiloxanes having cycloaliphatic epoxide or glycidyl ethergroups.

A wide variety of commercial epoxy resins are available and listed in"Handbook of Epoxy Resins" by Lee and Neville, McGraw Hill Book Company,New York (1967) and in "Epoxy Resin Technology" by P. F. Bruins, JohnWiley & Sons, New York (1968). Representative of the 1,3- and 1,4-cyclicethers which can be polymerized in accordance with this invention areoxetane, 3,3-bis(chloromethyl)oxetane, and tetrahydrofuran.

In particular, cyclic ethers which are readily available includepropylene oxide, oxetane, epichlorohydrin, tetrahydrofuran, styreneoxide, cyclohexeneoxide, vinylcyclohexene oxide, glycidol, glycidylmethacrylate, octylene oxide, phenyl glycidyl ether, 1,2-butane oxide,diglycidyl ether of bisphenol A (e.g., "Epon 828" and "DER 331"),vinylcyclohexene dioxide (e.g., "ERL-4206"),3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (e.g.,"ERL-4221"), 3,4-epoxy-6-methylcyclohexylmethyl3,4-epoxy-6-methylcyclohexanecarboxylate (e.g.,"ERL-4201"),bis(3,4-epoxy 6-methylcyclohexylmethyl)adipate (e.g., "ERL-4289"),aliphatic epoxy modified with polypropylene glycol (e.g., "ERL-4050" and"ERL-4052"), dipentene dioxide (e.g., "ERL-4269"), epoxidizedpolybutadiene (e.g., "Oxiron 2001"), silicone epoxy (e.g., "Syl-Kem90"), 1,4-butanediol diglycidyl ether (e.g., Araldite RD-2),polyglycidyl ether of phenolformaldehyde novolak (e.g., "DER-431","Epi-Rez 521" and "DER-438"), resorcinol diglycidyl ether (e.g.,"Kopoxite"), polyglycol diepoxide (e.g., "DER 736"), polyacrylateepoxide (e.g., "Epocryl U-14"), urethane modified epoxide (e.g.,"QX3599"), polyfunctional flexible epoxides (e.g., "Flexibilizer 151"),and mixtures thereof as well as mixtures thereof with co-curatives,curing agents, or hardeners which also are well known (see Lee andNeville and Bruins, supra). Representative of the co-curatives ofhardeners which can be used are acid anhydrides such as nadic methylanhydride, cyclopentanetetracarboxylic dianhydride, pyromelliticanhydride, cis-1,2-cyclohexanedicarboxylic anhydride, and mixturesthereof.

As noted above, the organometallic compounds useful in combination withonium salts to provide the curing agents useful in the invention havethe formula

    L.sup.1 L.sup.2 L.sup.3 M,                                 I

Ligands L¹ to L³ are well known in the art of transition metalorganometallic compounds.

Ligand L¹ of general formula I is provided by any monomeric or polymericcompound having an accessible unsaturated group, i.e., an ethylenic,##STR1## group; acetylenic, --C.tbd.C-- group; or aromatic group whichhas accessible pi-electrons regardless of the total molecular weight ofthe compound. By "accessible", it is meant that the compound (orprecursor compound from which the accessible compound is prepared)bearing the unsaturated group is soluble in a reaction medium, such asan alcohol, e.g., methanol; a ketone, e.g., methyl ethyl ketone; anester, e.g., amyl acetate; a halocarbon, e.g., trichloroethylene; analkane, e.g., decalin; an aromatic hydrocarbon, e.g., anisole; an ether,e.g., tetrahydrofuran; etc, or that the compound is divisible into veryfine particles of high surface area so that the unsaturated group(including aromatic group) is sufficiently close to a metal atom to forma pi-bond between that unsaturated group and the metal atom. Bypolymeric compound, is meant, as explained below, that the ligand can bea group on a polymeric chain.

Illustrative of ligand L are the linear and cyclic ethylenic andacetylenic compounds having less than 100 carbon atoms, preferablyhaving less than 60 carbon atoms, and from zero to 10 hetero atomsselected from nitrogen, sulfur, non-peroxidic oxygen, phosphorous,arsenic, selenium, boron, antimony, tellurium, silicon, germanium, andtin, such as, for example, ethylene, acetylene, propylene,methylacetylene, 1-butene, 2-butene, diacetylene, butadiene,1,2-dimethylacetylene, cyclobutene, pentene, cyclopentene, hexene,cyclohexene, 1,3-cyclohexadiene, cyclopentadiene, 1,4-cyclohexadiene,cycloheptene, 1-octene, 4-octene, 3,4-dimethyl-3-hexene, and 1-decene;eta³ allyl, eta³ -pentenyl, norbornadiene, eta⁵ -cyclohexadienyl, eta⁶-cycloheptatriene, eta⁸ -cyclooctatetraene, and substituted andunsubstituted carbocyclic and heterocyclic aromatic ligands having up to25 rings and up to 100 carbon atoms and up to 10 hetero atoms selectedfrom nitrogen, sulfur, non-peroxidic oxygen, phosphorous, arsenic,selenium, boron, antimony, tellurium, silicon, germanium, and tin, suchas, for example, eta⁵ -cyclopentadienyl, benzene, mesitylene,hexamethylbenzene, fluorene, naphthalene, anthracene, chrysene, pyrene,eta⁷ - cycloheptatrienyl, triphenylmethane, paracyclophane,1,4-diphenylbutane, eta⁵ -pyrrole, eta-⁵ thiophene, eta⁵ -furan,pyridine, gamma-picoline, quinaldine, benzopyran, thiochrome,benzoxazine, indole, acridine, carbazole, triphenylene, silabenzene,arsabenzene, stibabenzene, 2,4,6-triphenylphosphabenzene, eta⁵-selenophene, dibenzostannepine, eta⁵ -tellurophene, phenothiarsine,selenanthrene, phenoxaphosphine, phenarsazine, phenatellurazine, eta⁵-methylcyclopentadienyl, eta⁵ -pentamethylcyclopentadienyl, and1-phenylborabenzene. Other suitable aromatic compounds can be found byconsulting any of many chemical handbooks.

As mentioned before, the ligand can be a unit of a polymer, for example,the phenyl group in polystyrene, poly(styrene-co-butadiene),poly(styrene-co-methyl methacrylate), poly(alpha-methylstyrene),polyvinylcarbazole, and polymethylphenylsiloxane; the cyclopentadienegroup in poly(vinylcyclopentadiene); the pyridine group inpoly(vinylpyridine), etc. Polymers having a weight average molecularweight up to 1,000,000 or more can be used. It is preferable that 5 to50 percent of the unsaturated or aromatic groups present in the polymerbe complexed with metallic cations.

Each ligand L¹ can be substituted by groups that do not interfere withthe complexing of the ligand with the metal atom or which do not reducethe solubility of the ligand to the extent that complexing with themetal atom does not take place. Examples of substituting groups, all ofwhich preferably have less than 30 carbon atoms and up to 10 heteroatoms selected from nitrogen, sulfur, non-peroxidic oxygen, phosphorus,arsenic, selenium, antimony, tellurium, silicon, germanium, tin, andboron, include hydrocarbyl groups such as methyl, ethyl, butyl, dodecyl,tetracosanyl, phenyl, benzyl, allyl, benzylidene, ethenyl, and ethynyl;hydrocarbyloxy groups such as methoxy, butoxy, and phenoxy;hydrocarbylmercapto groups such as methylmercapto (thiomethoxy),phenylmercapto (thiophenoxy); hydrocarbyloxycarbonyl such asmethoxycarbonyl and phenoxycarbonyl; hydrocarbylcarbonyl such as formyl,acetyl, and benzoyl; hydrocarbylcarbonyloxy such as acetoxy, benzoxy,and cyclohexanecarbonyloxy; hydrocarbylcarbonamido, e.g., acetamido,benzamido; azo, boryl; halo, e.g., chloro, iodo, bromo, and fluoro;hydroxy; cyano; nitro; nitroso, oxo; dimethylamino; diphenylphosphino,diphenylarsino; diphenylstibine; trimethylgermyl; tributylstannyl;methylseleno; ethyltelluro; and trimethylsiloxy; condensed rings such asbenzo, cyclopenta; naphtho, indeno; and the like.

Each ligand L² in formula I is provided by monodentate and polydentatecompounds preferably containing up to about 30 carbon atoms and up to 10hetero atoms selected from nitrogen, sulfur, non-peroxidic oxygen,phosphorous, arsenic, selenium, antimony, and tellurium, whereuponaddition to the metal atom, following loss of zero, one, or twohydrogens, the polydentate compounds preferably forming with the metal,M, a 4-, 5-, or 6-membered saturated or unsaturated ring. Examples ofsuitable monodentate compounds or groups are carbon monoxide, carbonsulfide, carbon selenide, carbon telluride, alcohols such as ethanol,butanol, and phenol; nitrosonium (i.e., NO⁺); compounds of Group VAelements such as ammonia, phosphine, trimethylamine, trimethylphosphine,triphenylamine, triphenylphosphine, triphenylarsine, triphenylstibine,tributylphosphite, isonitriles such as phenylisonitrile,butylisonitrile; carbene groups such as ethoxymethylcarbene,dithiomethoxycarbene; alkylidenes such as methylidene, ethylidene;suitable polydentate compounds or groups include1,2-bis(diphenylphosphino)ethane, 1,2-bis(diphenylarsino)ethane,bis(diphenylphosphino)methane, ethylenediamine, propylenediamine,diethylenetriamine, 1,3- diisocyanopropane, andhydridotripyrrazolyborate; the hydroxycarboxylic acids such as glycolicacid, lactic acid, salicylic acid; polyhydric phenols such as catecholand 2,2'-dihydroxybiphenyl; hydroxyamines such as ethanolamine,propanolamine, and 2-aminophenol; dithiocarbamates such asdiethyldithiocarbamate, dibenzyldithiocarbamate; xanthates such as ethylxanthate, phenyl xanthate; the dithiolenes such asbis(perfluoromethyl)-1,2-dithiolene; aminocarboxylic acids such asalanine, glycine and o-aminobenzoic acid; dicarboxylic diamines asoxalamide, biuret; diketones such as 2,4-pentanedione; hydroxyketonessuch as 2-hydroxyacetophenone; alpha-hydroxyoximes such assalicylaldoxime; ketoximes such as benzil oxime; and glyoximes such asdimethylglyoxime. Other suitable groups are the inorganic groups suchas, for example, CN⁻, SCN⁻, F⁻, OH⁻, Cl⁻, Br⁻, I⁻, and H⁻ and theorganic groups such as, for example, acetoxy, formyloxy, benzoyloxy,etc. As mentioned before, the ligand can be a unit of a polymer, forexample the amino group in poly(ethyleneamine); the phosphino group inpoly(4-vinylphenyldiphenylphosphine); the carboxylic acid group inpoly(acrylic acid); and the isonitrile group inpoly(4-vinylphenylisonitrile).

Suitable ligands L³ in formula I include any group having in itsstructure an atom with an unshared electron. Suitable groups can containany number of carbon atoms and hetero atoms but preferably contain lessthan 30 carbon atoms and up to 10 hetero atoms selected from nitrogen,sulfur, oxygen, phosphorus, arsenic, selenium, antimony, tellurium,silicon, germanium, tin, and boron. Examples of such groups arehydrocarbyl groups such as methyl, ethyl, propyl, hexyl, dodecyl,phenyl, tolyl, etc.; unsaturated hydrocarbyl groups such as vinyl, eta¹-allyl, eta¹ -butenyl, eta¹ -cyclohexenyl; the hydrocarbyl derivativesof a Group IVA element such as trimethylgermyl, triphenylstannyl,trimethylsilyl, and triphenyllead, etc.; and organic groups such asformyl, acetyl, propionyl, acryloyl, octadecoyl, benzoyl,toluenesulfonyl, oxalyl, malonyl, o-phthaloyl.

Also suitable as L³ is any group having in its structure two, three, orfour unshared electrons, with the proviso that only one electron isshared per metal M. Examples of such groups are CH₂, SiMe₂, SiPh₂,SnPh₂, GePh₂, SiMe, SiPh₂, SnPh, Si, and Sn.

M can be any element from the Periodic Groups IVB, Vs, VIB, VIIB, andVIIIB, such as, for example, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc,Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and Pt.

In general, radiation-induced polymerization of ethylenicallyunsaturated monomers and one of polyurethane precursors and epoxymonomers with latent curing agents comprising an organometallic compoundand an onium salt can be carried out at room temperature for themajority of energy curable compositions, although low temperature (e.g.,-10° C.) or elevated temperature (e.g., 30 to 200° C., preferably 50 to150° C.) can be used to subdue the exotherm of polymerization or toaccelerate the polymerization, respectively. Temperature ofpolymerization and amount of catalyst will vary and be dependent on theparticular curable composition used and the desired application of thepolymerized or cured product. The amount of curing agent to be used inthis invention should be sufficient to effect polymerization of thepolymerizable mixtures (i.e., a catalytically-effective amount) underthe desired use conditions. Such amount generally will be in the rangeof about 0.1 to 20 weight percent, and preferably 0.1 to 10.0 weightpercent, based on the weight of curable composition.

While not wishing to be bound by theory, We propose that when specifiedorganometallic compounds are irradiated in the presence of suitableoxidizing agents such as onium salts, intermediate compounds areproduced which can affect the curing of epoxides, urethanes, and vinylmonomers. It is believed that the transition metal-transition metal ormetal-L: sigma bond cleaves homolytically upon photolysis. Evidence forthis homolytic cleavage is provided for some organometallic compoundssuch as [CpFe(CO)₂ ]₂ and Mn₂ (CO)₁₀ and involves the abstraction of Clfrom CCL₄ subsequent to photolysis. (G. Geoffrey and M. Wrighton,"Organometallic Photochemistry," Academic Press, NY (1979), Chapters 2and 8, particularly p. 138). In other cases, spectroscopic data providessuch evidence (O. Hackelberg, A. Wojcicki Inorg. Chem. Acta. 1980, 44,L63; R. G. Severson, A. Wojcicki J. Organomet. Chem. 1978, 157, 173).The product(s) of this bond homolysis then react with the oxidizingagent. By this process, the catalytic species for the polymerization ofeither the polyurethane precursors or epoxy monomers is derived from theorganometallic compound, and, simultaneously the free radical initiatorfor the polymerization of the ethylenically unsaturated monomers isderived from the oxidizing agent. In the limit, cleavage of the sigmabond by one photon can ultimately lead to the production of twoorganometallic-derived species and two free radical initiators. Itshould be noted that competing or secondary photo processes, such asdissociation of a carbonyl ligand, can occur. Such processes, however,occur in such a manner or to such an extent that the effective catalyticspecies and initiator are still produced so as to effect curing of thecomposition.

Solvents, preferably organic can be used to assist in dissolution of thecuring agent in the ethylenically-unsaturated monomer, and eitherpolyurethane precursors or epoxy monomers, and as a processing aid.Representative solvents include acetone, methyl ethyl ketone,cyclopentanone, methyl cellosolve acetate, methylene chloride,nitromethane, methyl formate, acetonitrile, gamma-butyrolactone, and1,2-dimethoxyethane (glyme). In some applications, it may beadvantageous to adsorb the curing agent onto an inert support such assilica, alumina, clays, etc., as deseribed in U.S. Pat. No. 4,677,137.

For those compositions of the invention which are radiation-sensitive,i.e., the compositions containing ethylenically unsaturated monomers andeither polyurethane precursors or epoxy monomers and as curing agent acombination of an organometallic compound of Formula I and an onium saltof Formula II, any source of radiation including electron beam radiationand radiation sources emitting active radiation in the ultraviolet andvisible region of the spectrum (e.g., about 200 to 800 nm) can be used.Suitable sources of radiation include mercury vapor discharge lamps,carbon arcs, tungsten lamps, xenon lamps, lasers, sunlight, etc. Therequired amount of exposure to effect polymerization is dependent uponsuch factors as the identity and concentrations of the organometalliccompound and onium salt, the particular ethylenically unsaturatedmonomer, polyurethane precursors, and epoxy monomers, the thickness ofthe exposed material, type of substrate, intensity of the radiationsource and amount of heat associated with the radiation.

Thermal polymerization using direct heating or infrared electromagneticradiation, as is known in the art, can be used to cureethylenically-unsaturated monomers and either polyurethane precursors orepoxy monomers according to he teachings of this invention.

It is within the scope of this invention to include two-stagepolymerization (curing), by first activating curing agent by irradiatingthe curable compositions and subsequently thermally curing the activatedprecursor so obtained, the irradiation temperature being below thetemperature employed for the subsequent heat-curing. These activatedprecursors may normally be cured at temperatures which are substantiallylower than those required for the direct thermal curing, with anadvantage in the range from 50 to 110° C. This two-stage curing alsomakes it possible to control the polymerization in a particularly simpleand advantageous manner.

Adjuvants such as solvents, pigments, abrasive granules, stabilizers,light stabilizers, antioxidants, flow agents, bodying agents, flattingagents, colorants, inert fillers, binders, blowing agents, fungicides,bacteriocides, surfactants, plasticizers, and other additives as knownto those skilled in the art can be added to the compositions of thisinvention. These can be added in an amount effective for their intendedpurpose.

Compositions of this invention are useful for coatings, foams, shapedarticles, adhesives, filled or reinforced composites, abrasives,caulking and sealing compounds, casting and molding compounds, pottingand encapsulated compounds, impregnating and coating compounds, andother applications which are known to those skilled in the art.

Compositions of this invention may be applied, preferably as a liquid,to a substrate such as steel, aluminum, copper, cadmium, zinc, glass,paper, wood, or various plastic films such as poly(ethyleneterephthalate), plasticized poly(vinylchloride), poly(propylene),poly(ethylene), and the like, and irradiated. By polymerizing part ofthe coating, as by irradiation through a mask, those sections which havenot been exposed may be washed with a solvent to remove theunpolymerized portions while leaving the photopolymerized, insolubleportions in place. Thus, compositions of this invention may be used inthe production of articles useful in the graphic arts such as printingplates and printed circuits. Methods of producing printing plates andprinted circuits from photopolymerizing compositions are well known inthe art (see for example British Patent Specification No. 1,495,746).

Objects and advantages of this invention are further illustrated by thefollowing examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this invention. In the examples,all parts are parts by weight unless indicated otherwise. All exampleswere prepared in ambient atmosphere (presence of oxygen and water)unless indicated otherwise. In the examples:

Me=methyl

Ph=phenyl

Cp=cyclopentadienyl

EXAMPLE 1

The organometallic compounds, [CpFe(CO)₂ ]₂, Mn₂ (CO)₁₀, Re₂ (CO)₁₀ and[CpMo(CO)₃ ]₂ were obtained from Pressure Chemical Company and usedwithout further purification. The other compounds were prepared usingstandard organometallic synthetic techniques. The procedure used will beillustrated for the preparation of CpFe(CO)₂ SnPh₃.

The anion, CpFe(CO)₂, was produced by reducing 3.0g of [CpFe(CO)₂ ]₂with 0.41g of sodium and 0.50g of benzophenone in 200 mL of freshlydistilled tetrahydrofuran under an atmosphere of argon. The reaction wasallowed to proceed for about 24 hours by which time the startingmaterial had all been reduced to the anion as indicated by infraredspectroscopy (IR). To the solution of the anion was added, under argon,6.5 g of ClSnPh: as a solid. The reaction was stirred until the anionwas consumed as shown by IR. The reaction vessel was opened to air andthe solvent removed under reduced pressure. The solid residue was takenup in methylene chloride and passed down a short silica gel column.Crytals were obtained by removing the methylene chloride under reducedpressure and adding heptane. The product was identified by IR, nuclearmagnetic resonance spectroscopy (NMR), elemental analysis, and meltingpoint. In a similar manner all the other materials in Table I wereprepared.

These compounds are used in subsequent examples.

                  TABLE I                                                         ______________________________________                                        Characterization of Compounds                                                 Elemental Analysis                                                            (Report/Calculated)                                                                                            Melting                                      Compound      % C        % H     Point (°C.)                           ______________________________________                                        CpFe(CO).sub.2 SnPh.sub.3                                                                   57.0/57.0  3.8/3.8 135-136                                      CpFe(CO).sub.2 GePh.sub.3                                                                   62.3/62.4  4.2/4.2 159-160                                      CpFe(CO).sub.2 PbPh.sub.3                                                     [CpFe(CO).sub.2 ].sub.2 SnPh.sub.2                                                          49.7/49.8  3.3/3.2 146-149                                      (CO).sub.5 MnSnPh.sub.3                                                                     51.0/50.7  2.8/2.8 146-149                                      (CO).sub.5 MnPbPh.sub.3                                                       [(CO).sub.5 Mn].sub.2 SnPh.sub.2                                                            39.9/39.8  1.6/1.5 138-139                                      (CO).sub.5 ReSnPh.sub.3                                                       CpMoSnPh.sub.3                                                                              52.6/52.5  3.4/3.4 213-214                                      ______________________________________                                    

EXAMPLE 2

Several organometallic compounds were prepared according to literaturemethods. CpW(CO)₃ (CH₃) was prepared according to the method of T. S.Piper, G. Wilkinson, Inorg. Nucl. Chem., 1956, 3, 104-124. [CpW(CO)₃ ]₂was prepared according to the method of R. Birdwhistell, P. Hackett, A.R. Manning, J. Organomet. Chem., 1978, 157, 239. CpFe(CO)₂ SiPh₃ wasprepared according to the method of G. Cerveau, E. Colomer, R. Corriv,W. E. Douglas, J. Organomet. Chem., 1977, 135, 373, 386. The method ofJ. P. Bibler, A. Wojcicki, J. Amer. Chem. Soc., 1966, 88, 4862 was usedto prepare CpFe(CO)₂ (CHPh₂), and that of R. B. King, M. B. Bisnette, J.Organomet. Chem., 1964, 2, 15-37, to prepare CpFe(CO)₂ (COPh). Thepreparation of CpPtMe₃ has been described in U.S. Pat. No. 4,600,484.

These compounds are used in subsequent examples.

EXAMPLE 3 (Comparative)

This example illustrates the use of an organometallic compoundcontaining a transition metal-transition metal single bond in the curingagent to photocatalyze the formation of polyurethane. A stock solutionof 8.02 g 4,4,-methylenebis(cyclohexylisocyanate) (Desmodur™ W, a MobayCorp., Pittsburgh, PA) and 11.20 g polyethylene glycol MW400 (Carbowax™400, Union Carbide, Danbury, CT) was prepared. To a solution of 0.01 g[CpFe(CO)₂ ]₂ and 0.02 g PF₂ I⁺ PF₆ ⁻ in 0.1 g gamma-butyrolactone wasadded 1.25 g of the stock solution. The sample was photocured to a solidusing a Kodak™ Carousel™ projector in 12 minutes.

Three samples were prepared as above, except the iron dimer and iodoniumsalt were added as follows: sample (a), 0.01 g [CpFe(CO)₂ ]₂, 0.03 g Ph₂I⁺ PF₆ ⁻ ; sample (b), 0.01 g [CpFe(CO)₂ ]₂ ; sample (c), 0.03 g Ph₂ I⁺PF₆ ⁻ ; (a) was left in the dark while samples (b) and (c) wereirradiated as above. None of the three samples showed evidence of anycuring, no obvious change in viscosity as evidence, after 20 minutes.

EXAMPLE 4 (Comparative)

This example illustrates the use of an organometallic compoundcontaining a transition metal-carbon single bond in the curing agent tophotocatalyze the formation of polyurethane. 0.52 g Desmodur W(4,4'-methylene bis (cyclohexyl isocyanate)) and 0.72 g Carbowax 400(polyol) were combined and added to ca. 0.01 g CpPt(CH₃)₃ (Cp=eta⁵-cyclopentadienyl) which had been dissolved in ca. 0.15 ml of a mixtureof CH₂ Cl₂ and gamma-butyrolactone. The resulting mixture was irradiatedwith a Hanovia™ 450 watt medium pressure mercury arc lamp throughPyrex™. Complete cure was achieved within 12 minutes irradiation time.

EXAMPLE 5

This example describes the photocuring of Henkel Duo-Cure™ (HenkelCorp., Minneapolis, MN) resins. The Henkel Duo-Cure™ resins arepolyol/aliphatic polyisocyanate and multifunctional acrylate systemscontaining no curing agents. The resins are dual curing resins, and areclaimed to form interpenetrating networks (IPN's) when properly cured.

Samples were prepared, 2.0 g in size, using 77 parts Henkel Duo-Cure172A, 23 parts Duo-Cure 172B, 0.5 parts [CpFe(CO)₂ ]₂, and 1 part Ph₂ I⁺PF₆ ⁻. One sample was cured in the vial using a suntan lamp, cured in<3.0 minutes to a clear, hard mass. The other sample was coated on atongue depressor and exposed to the suntan lamp. Curing occurred in 15seconds, to yield a clear, hard, sandable coating. Infrared spectra ofthin coatings on salt plates showed conversion of the isocyanate tourethane upon exposure to sunlamp radiation.

EXAMPLE 6 (Comparative)

This example illustrates the photocuring of polyurethane precursors topolyurethanes in the presence and absence of 0: using transitionmetal-transition metal bond containing organometallic compounds andonium salt as curing agent.

A mixture of 10 mg [CpFe(CO)₃ ]₃, 30 mg Ph₃ I⁺ PF₆ ⁻, 0.1 ggamma-butyrolactone, 0.83 g Desmodur™ W (4,4'-methylenebis(cyclohexylisocyanate)), and 1.17 g polyethyleneglycol(MW=400) was divided in half. One half was bubbled with N₂ for 2-3minutes, the other left open to the atmosphere. Both samples wereirradiated simultaneously with the output of a 450 watt Hanovia mercurylamp, filtered through Pyrex and a water infrared filter. Both samplescured after 10.0 minutes irradiation. This demonstrates that in thepresence of onium salt, curing occurs with or without 0₂ present.

EXAMPLE 7 (Comparative)

This example describes the photocuring of polyurethane precursors usingtransition metal containing organometallic compounds and iodonium andsulfonium salts. A stock solution was prepared from 7 parts Desmodur W,1.9 parts butanediol, and 0.5 parts trimethylolpropane. Samples wereprepared as in Example 3 using 1.25 g of the stock solution, 0.01 gneutral metal-metal bonded compound and 0.015 g Ph₂ I⁺ PF₆ ⁻ in 0.05 ggamma-butyrolactone. Irradiations were carried out on a 450 W Hanoviamedium pressure mercury arc through Pyrex. Alternatively, thesecompositions can be cured thermally.

                  TABLE II                                                        ______________________________________                                        Iodonium and Sulfonium Salts                                                  Organometallic                                                                              Cure time, minutes                                              Compound      PH.sub.2 I.sup.+ PF.sub.6.sup.-                                                          Ph.sub.3 S.sup.+ PF.sub.6.sup.-                      ______________________________________                                        [Co(CO).sub.4 ].sub.2                                                                       6.0        >100                                                 [CpFe(CO).sub.2 ].sub.2                                                                     9.0        20-25                                                [Mn(CO).sub.5 ].sub.2                                                                       12-20       7-12                                                [Re(CO).sub.5 ].sub.2                                                                       20-40      20-40                                                Co.sub.4 (CO).sub.12                                                                        40-55      55-66                                                [CpMo(CO).sub.3 ].sub.2                                                                     55-67      60-66                                                Fe.sub.2 (CO).sub.9                                                                         ca. 60     --                                                   ______________________________________                                    

EXAMPLE 8 (Comparative)

This provides further examples of bicomponent curing agents whereinorganometallic compounds contain transition metal-carbon bonds which areeffective in the curing agent for polyurethane precursors. A stocksolution of polyurethane precursors was prepared by mixing 23.1 gDesmodur W and 32.6 g Carbowax 400 and shaking well before use. Sampleswere prepared by dissolving 10 mg catalyst and 20 mg diphenyliodoniumhexafluorophosphate (if used) in 0.2 g CH₂ Cl₂. 2.0 g stock solution wasadded in the dark, and samples were then irradiated under a HanoviaQuartz Utility Lamp. The temperature of samples under the lamp reachedca. 50° C. within 10 min. The time to a viscocity increase is noted inTable III, and "cure time" is the time for a sample to become so viscousthat it would not flow. "Partial cure" is indicated when, within 30 minirradiation, the sample became more viscous but would still flow.

                  TABLE III                                                       ______________________________________                                        Curing of Polyurethane Precursors                                                                 Cure Rates, min                                                               Viscocity                                                                     Increase                                                                             Cured                                              ______________________________________                                        CpPtMe.sub.3           7       30                                             CpPtMe.sub.3 + iodonium                                                                              7       30                                             CpW(CO).sub.3 Me      30       partial                                        CpW(CO).sub.3 Me + iodonium                                                                         30       partial                                        [(PMe.sub.2 Ph).sub.2 PtMe.sub.3 (acetone)] + PF.sub.6.sup.-a                                       13       partial                                        [CpFe(CO).sub.2)].sub.2 + iodonium                                                                   9       30                                             ______________________________________                                         .sup.a included for purposes of comparison                               

The data show curing occurs with or without iodonium salts. In somecases, adventitious oxygen can provide a suitable oxidizing agent.However, the use of onium salts is preferred since it is much easier tocontrol the organometallic/oxidizing agent ratio.

EXAMPLE 9 (Comparative)

This example describes the use of the curing agent containing anorganometallic compound containing a transition metal-carbon bond tocure epoxies. Each sample was prepared by dissolving 10 mg catalyst and20 mg diphenyliodonium hexafluorophosphate (if used) in 0.2 g CH₂ Cl₂.2.0 g cyclohexene oxide was added in the dark, and samples were thenirradiated under a Hanovia Quartz Utility lamp. Initial formation ofpolymer was tested by placing a few drops of the sample in about 2 mLmethanol. Formation of precipitate indicated that polymer had formed.Further polymerization resulted in a viscocity increase in the sample.Results are indicated in Table IV.

                  TABLE IV                                                        ______________________________________                                                                       Viscosity                                                          Precipitate                                                                              increased,                                     Curing Agent        formed, min.                                                                             min.                                           ______________________________________                                        CpPtMe.sub.3        no cure    no cure                                        CpPtMe.sub.3 + iodonium                                                                             3.5      30                                             CpW(CO).sub.3 Me + iodonium                                                                       3          30                                             (PMe.sub.2 Ph).sub.2 PtMe.sub.3 (acetone) + PF.sub.6 -.sup.a                                      2          no further                                                                    cure                                           [CpFe(CO).sub.2 ].sub.2 + iodonium                                                                2          30                                             ______________________________________                                         .sup.a included for proposes of comparison.                              

EXAMPLE 10 (Comparative)

Examples of the ability of curing agent containing transitionmetal-transition metal bonded and M-L³ type organometallic compounds andonium salt to photoinitiate the cure of epoxies are provided here. Thetests were carried out in the following manner: Into a glass vial wereweighed out 0.10g of the desired organometallic compound and/or 0.20gdiphenyliodonium hexafluorophosphate (3M Company, recrystallized fromacetone/isopropanol). Then, the following operations were carried outunder subdued light, 0.3g of gamma-butyrolactone, 2.0g cyclohexene oxide(Aldrich Chemical Company, distilled), 5.0g of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (ERL-4221,Union Carbide Company) were added to prepare the coating solution. Thesolutions were coated onto 76 micrometers (3 mil) polyvinylidenechloride subbed polyester (3M Company) using a #22 wire wound rod. Thesample coatings were exposed, in air, to a 275 watt G.E. sunlamp at adistance of 10cm. The time to "set to cotton" is recorded in Table V,that is the time needed to cure the coating so that when it is touchedwith a cotton ball, it leaves no smear or picks up no cotton threads.This test establishes the time required to cure the coating. Under theconditions of this test, the diphenyliodonium hexafluorophosphate alonerequires greater than 10 min to cure.

                  TABLE V                                                         ______________________________________                                        Photoinitiation of Epoxy Cure                                                                Cure Time.sup.a                                                                 No Onium  Onium Salt                                         Compound         Salt Added                                                                              Added                                              ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                        >10       1                                                  CpFe(CO).sub.2 SnPh.sub.3                                                                      >10       5                                                  CpFe CO).sub.2 GePh.sub.3                                                                      >10       5                                                  [CpFe(CO).sub.2 ].sub.2 SnPh.sub.2                                                             >10       3                                                  Mn.sub.2 (CO).sub.10                                                                           >10       1                                                  (CO).sub.5 MnSnPh.sub.3                                                                        >10       4                                                  [(CO).sub.5 Mn].sub.2 SnPh.sub.2                                                               >10       3                                                  Re2(CO)10          1         1.5                                              CpMo(CO).sub.3 SnPh.sub.3                                                                        8       4                                                  ______________________________________                                         .sup.a time in minutes to cure.                                          

EXAMPLE 11 (Comparative)

To further demonstrate the activity of the curing agent, a series ofexperiments were carried out in another epoxy and/or acrylatecomposition. The organometallic compound, with and without the oniumsalt, was photolyzed in presence of an epoxy or acrylate. The specificsystem used is as follows: methyl acrylate was distilled fromhydoquinone and stored cold until ready for use. Cyclohexene oxide wasused as obtained from Aldrich. The organometallic compounds wereobtained from commercial sources. Diphenyliodonium hexafluorophosphatewas recrystallized from acetone/isopropanol. All experiments were doneas 100% solids, except as noted.

In a small vial was placed 0.02 g of the organometallic compoundwith/without 0.04 g of the iodonium salt along with 2 g of the desiredmonomer. For the acrylate tests, the solutions were purged with N: for60 sec before and continuously during the photolysis. The epoxy testswere performed without purging, vials open to the air. The light sourcewas one 15 watt daylight fluorescent bulb. In Table VI below, the curetimes represent the time required to reach the same degree of cure,usually gelation of the solution. Alternatively, the acrylatecompositions can be cured thermally.

                  TABLE VI                                                        ______________________________________                                        Photoinitiated Cure Times of Epoxy                                            and Acrylate Compositions.sup.a                                               Catalyst System    Epoxy   Acrylate                                           ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                          >900    >600                                               [CpFe(CO).sub.2 ].sub.2 /iodonium                                                                  60    30                                                 Mn.sub.2 (CO).sub.10                                                                             >900    >600                                               Mn.sub.2 (CO).sub.10 /iodonium                                                                    200    45                                                 Re.sub.2 (CO).sub.10                                                                             >900    360                                                Re.sub.2 (CO).sub.10 /iodonium                                                                    200    60                                                 Co.sub.2 (CO).sub.8                                                                              .sup.b  .sup.b                                             Co.sub.2 (CO).sub.8 /iodonium                                                                    .sup.c  200                                                Co.sub.4 (CO) .sub.12                                                                            .sup.b  .sup.b                                             Co.sub.4 (CO).sub.12 /iodonium.sup.d                                                             >900    80                                                 iodonium           >900    >300                                               ______________________________________                                         .sup.a Cure time in seconds.                                                  .sup.b Not done.                                                              .sup.c Reacted in the dark upon mixing.                                       .sup.d 10% by wt. gammabutyrolactone added.                              

EXAMPLE 12 (Comparative)

This example demonstrates the ability of transition metal-transitionmetal bonded or ML: type organometallic compounds to photoinitiate thecure of ethylenically-unsaturated compounds in the presence of iodoniumsalts. The tests were carried out in the following manner: Into a glassvial were weighed out 0.05g of the desired organometallic compoundand/or 0.10g diphenyliodonium hexafluorophosphate (3M Company,recrystallized from acetone/isopropanol). Then, the following operationswere carried out under subdued light: 0.2g of gamma-butyrolactone, 5.0gmethyl acrylate (Aldrich Chemical Company, distilled from hydroquinone),5.0g of pentaerythritol tetraacrylate (SR-295, Sartomer Company) wereadded to prepare the coating solution. The solutions were coated onto 76micrometers (3 mil) polyvinylidene chloride subbed polyester (3MCompany) using a #22 wire wound rod. The sample coatings were overlayed,with a second sheet of polyester and exposed to two 15 watt Sylvaniablacklight bulbs at a distance of 2 cm. The time required to produce anontacky cured coating was recorded. Under the conditions of this test,the diphenyliodonium hexafluorophosphate alone requires greater than 15min to cure.

                  TABLE VII                                                       ______________________________________                                        Curing of Ethylenically Unsaturated Monomers                                                  Cure Time                                                                       No Onium  Onium Salt                                        Organometallic Compound                                                                         Salt Added                                                                              Added                                             ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                         >600      15                                                CpFe(CO).sub.2 SnPh.sub.3                                                                       >600      120                                               CpFe(CO).sub.2 GePh.sub.3                                                                       >600      120                                               [CpFe(CO).sub.2 ].sub.2 SnPh.sub.2                                                              >600      60                                                Mn.sub.2 (CO).sub.10                                                                            >600      <15                                               (CO).sub.5 MnSnPh.sub.3                                                                          300      300                                               [(CO).sub.5 Mn].sub.2 SnPh.sub.2                                                                  60      30                                                Re.sub.2 (CO).sub.10                                                                             120      60                                                [CpMo(CO).sub.3 ].sub.2.sup.b                                                                   >600      30                                                CpMo(CO).sub.3 SnPh.sub.3                                                                       >600      240                                               ______________________________________                                         .sup.a time in seconds to cure.                                               .sup.b saturated solution, <0.01 g dissolved.                            

EXAMPLE 13 (Comparative)

Further examples of the curing of ethylenically unsaturated monomer (25g of pentaerythritol tetraacrylate in 225g acetonitrile) or epoxymonomer (cyclohexene oxide) are provided here. A curable compositionconsisted of 0.01g of the organometallic compound or 0.02g ofdiphenyliodonium hexafluorophosphate or these same amounts of bothcompounds added to either monomer. The light sources used were for UVexposure, about 360 nm, two 15 watt G.E. blacklite bulbs and for thevisible, a Kodak Carousel Projector or the projector with a 440 nmfilter. The initiation of polymerization was detected by solutiongelation for the acrylate and for the epoxy the precipitation of thepolymer from a 2% ammonia/methanol solution Free radical systems werepurged with N₂ for 2 minutes before and continuously during irradiationwhile the cationic samples were left open to the air without purging.Sample size was 2 to 3 ml in a 13×100 mm pyrex test tube. The results ofthese tests are shown in Table VIII.

                  TABLE VII                                                       ______________________________________                                        Photoinitiated Cure Times of                                                  Epoxy and Acrylate Compositions.sup.a                                         Curing Agent       Epoxy   Acrylate                                           ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                          >180.sup.b                                                                            >300.sup.b                                         [CpFe(CO).sub.2 ].sub.2 /iodonium.sup.c                                                            90.sup.b                                                                             <5.sup.b                                          [CpFe(CO).sub.2 ].sub.2 /iodonium.sup.c                                                            90.sup.d                                                                             <5.sup.d                                          Mn.sub.2 (CO).sub.10                                                                             >180.sup.b                                                                            >300.sup.b                                                            >180.sup.e                                                                            >300.sup.e                                         Mn.sub.2 (CO).sub.10 /iodonium.sup.c                                                             >180.sup.b                                                                             <10.sup.b                                                            >180.sup.e                                                                             <10.sup.e                                         ______________________________________                                         .sup.a Cure times given in seconds.                                           .sup.b Unfiltered projector as light source.                                  .sup.c The diphenyliodonium salt showed no indication of polymerization b     itself under these same conditions.                                           .sup.d 440 nm filter used with the projector.                                 .sup.e Blacklite used as the light source, about 360 nm.                 

EXAMPLE 14 (Comparative)

Examples of the photocuring of ethylenically unsaturated monomers usingtransition metal-transition metal bond containing organometalliccompounds and iodonium salts are given here.

Samples were prepared as 1.0 g methyl acrylate containing 0.01 gmetal-metal bond containing complex and 0.015 g Ph₂ I⁺ PF₆ ⁻. Up to 0.05g butyrolactone or methylene chloride were used to dissolve thephotocatalyst systems. Samples were bubbled with N₂ and irradiated usinga Kodak Carousel slide projector, with a 360 nm cutoff filter, and thetime required to cure the sample recorded in Table IX. Alternatively,compositions could be cured thermally.

                  TABLE IX                                                        ______________________________________                                        Curing of Ethylenically-Unsaturated Monomers                                  Compound                                                                      and Ph.sub.2 I.sup.+ PF.sub.6.sup.-                                                     Conditions  Cure Time                                               ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                 irrad.      30 sec, slow dark reaction                              Mn.sub.2 (CO).sub.10                                                                    irrad.      30 sec, no dark reaction                                [CpMo(CO).sub.3 ].sub.2                                                                 irrad.      45 sec, no dark reaction                                [Re(CO).sub.5 ].sub.2                                                                   irrad.       8 min, no dark reaction                                Co4(CO).sub.12                                                                          irrad.      Minutes, slow dark reaction                             Co2(CO).sub.8                                                                           Dark        Cures during deoxygenation                              ______________________________________                                    

EXAMPLE 15 (Comparative)

This example describes the curing of ethylenically unsaturated monomerswith transition metal-carbon bonded organometallic compounds. Eachsample was prepared by dissolving 10 mg catalyst and 20 mgdiphenyliodonium hexafluorophosphate (if used) in 0.2 ggamma-butyrolactone. 2.0 g methyl acrylate (distilled to removeinhibitors) was added in the dark and nitrogen was bubbled through thesample for 2 min to remove oxygen. Samples were then irradiated in frontof a Kodak Carousel Projector containing a 360 nm cutoff filter. If nocuring occurred in 15 min, the sample was then irradiated for 15 minunder a Hanovia Quartz Utility lamp. In Table X, "cure time" refers tothe time required for a sample to solidify. Alternatively, compositionscould be cured thermally.

                  TABLE X                                                         ______________________________________                                        Curing of Ethylenically Unsaturated Monomer                                   Curing Agent          Cure time, min                                          ______________________________________                                        CpPtMe.sub.3          15 (Hanovia)                                            CpPtMe.sub.3 + iodonium                                                                              6 (Kodak)                                              CpW(CO).sub.3 Me      no cure                                                 CpW(CO).sub.3 Me + iodonium                                                                          3.5                                                    [CpFe(CO).sub.2 ].sub.2 + iodonium.sup.a                                                             0.5 (dark cure)                                        ______________________________________                                         .sup.a included for purposes of comparison                               

EXAMPLE 16 (Comparative)

This example describes the use of [CpW(CO)₃ ]₂ to cure polyurethaneprecursors, epoxies or ethylenically unsaturated monomers. Each samplecontained 0.01 g [CpW(CO)₃ ]₂ and 0.02 g diphenyliodoniumhexafluorophosphate (if used) in 0.25 g gamma-butyrolactone,/ to whichwas added 2.0 g of precursor or monomer in a vial. Irradiation was thenperformed with a Kodak Carousel Projector (9 inches away), modified witha 360 nm filter. With a urethane precursor stock solution (prepared asin Example 4), in the presence or absence of onium salt, partial curingto produce a clear solution, occurred in 2 hour irradiation time. Uponstanding in room light for 24 hours, an increase in viscosity occurred.

When cyclohexeneoxide was used, and the curing agent consisted of[CpW(CO)₃ ]₂ and onium salt, vigorous, exothermic curing occurred within3 min of irradiation.

When methyl acrylate was used as monomer, no curing occurred in theabsence of onium salt. With onium salt present, the sample becameviscous within 4 min and solid within 8 min of irradiation time.

Alternatively, these compositions can be cured thermally.

EXAMPLE 17 (Comparative)

To demonstrate the utility of the curing agent for curing ofpolyurethane precursors, epoxies and vinyl monomers for the case wherethe organometallic compound contains a single bond between a transitionmetal and a Group IVA element, the following samples were prepared. In avial, 0.01 g of organometallic compound, 0.02 g of diphenyliodoniumhexafluorophosphate (if used, as indicated below), and 0.25 g ofgamma-butyrolactone were gently agitated until dissolution of theorganometallic compound was complete. 2.0 g of polyurethane precursorsor monomer was added in reduced light, the vial was capped, and thesample irradiated in front of a Kodak Carousel projector fitted with a360 nm cutoff filler at a distance of nine inches, and at roomtemperature (about 25° C.). Particular details and any experimentalvariations are indicated in Table XI.

                  TABLE XI                                                        ______________________________________                                        Cure Times: Photoinitiated Curing of Polyurethane Precursors                  Epoxies and Vinyl Monomers with Transition Metal-                             Group IVA Compounds                                                           Catalyst System                                                                              PolyUrethane.sup.a                                                                        Epoxy.sup.b                                                                            Vinyl.sup.c                               ______________________________________                                        [CpFe(CO).sub.2 ].sub.2.sup.d                                                                120 min (VV).sup.e                                                                        f        no cure                                   [CpFe(CO).sub.2 ].sub.2 /iodonium.sup.d                                                       60 min (VV)                                                                               30 sec  1.8 min                                   CpFe(CO).sub.2 (CH.sub.2 Ph)                                                                  40 min (V) f        no cure                                   CpFe(CO).sub.2 (CH.sub.2 Ph)/iodo-                                                            40 min (V)   12 min  23 min                                   nium                                                                          CpFe(CO).sub.2 (COPh)                                                                        120 min (V).sup.e                                                                         f        no cure                                   CpFe(CO).sub.2 (COPh)/iodo-                                                                  120 min (V).sup.e                                                                           5 min  48 hr.sup.g                               nium                                                                          CpFe(CO).sub.2 (SiPh.sub.3)                                                                   45 min (V).sup.h                                                                         f        no cure                                   CpFe(CO).sub.2 (SiPh.sub.3)/iodo-                                                             45 min (V).sup.h                                                                           5 min  48 hr.sup.g                               nium                                                                          CpFe(CO).sub.2 (GePh.sub.3)                                                                   36 min (V).sup.h                                                                         f        no cure                                   CpFe(CO).sub.2 (GEPh.sub.3)/iodo-                                                             36 min (V).sup.h                                                                         2.75 min no cure                                   nium                                                                          CpFe(CO).sub.2 (SnPh.sub.3)                                                                   36 min (S).sup.h                                                                         f        no cure                                   CpFe(CO).sub.2 (SnPh.sub.3 )/iodo-                                                            36 min (V).sup.h                                                                           2 min  no cure                                   nium                                                                          CpFe(CO).sub.2 (PbPh.sub.3)                                                                   45 min (S).sup.h                                                                         f        no cure                                   CpFe(CO).sub.2 (PbPh.sub.3)/iodo-                                                             33 min (VV).sup.h                                                                        no cure  no cure                                   nium                                                                          ______________________________________                                         .sup.a Polyurethane precursors are from a stock solution consisting of        23.1 g of Desmodur ™ W and 32.6 g of Carbowax 400. Cure times are          followed by an indication in parentheses of extent of cure, where V =         viscous, VV = very viscous, S = solid.                                        .sup.b Monomer is cyclohexene oxide, purified by distillation. Cure time      is defined as the time necessary to observe formation of precipitate when     one drop of sample is placed in 2 ml of methanol.                             .sup.c Monomer is methyl acrylate, purified prior to use by distillation      under pressure. After monomer addition but before irradiation, samples        were deoxygenated by bubbling a stream of nitrogen gas through the            solution for 2 min, with care being taken to prevent any light from           reaching the sample during deoxygenation. Cure is defined by an increase      in solution viscosity or a sudden exotherm indicating rapid polymerizatio     (also accompanied by a sudden increase in viscosity).                         .sup.d Included for purposes of comparison to data in other Tables.           .sup.e 60 min irradiation with Carousel Projector, followed by 60 minutes     of irradiation in room (fluorescent) light.                                   .sup.f This particular combination was not tested.                            .sup.g 30 minutes irradiation with Kodak projector, following by 30           minutes irradiation under a Hanovia Quartz Utility Lamp (6 inches from        bulb), followed by sample storage/irradiation in room (fluorescent) light     .sup.h Irradiation with Hanovia Quartz Utility Lamp (15 cm from bulb) in      place of the Kodak Projector.                                            

EXAMPLE 18

This example illustrates the dual curing of polyurethane precursors andethylenically-unsaturated monomers using the curing agent [CpFe(CO)₂ ]₂/Ph₂ I⁺ PF₆ ⁻.

Samples 1.25 g in size, were prepared from stock solutions of 2.08 partsDesmodur™ W (4,4'-methylenebis(cyclohexylisocyanate)), 2.92 partspolyethyleneglycol (MW=400), 5.0 parts methyl acrylate (freshlydistilled), and 0.05 parts [CpFe(CO)₂ ]₂. To half of this stock solutionwas added 0.062 parts Ph₂ I⁺ PF₆ ⁻. Mole ratios for iodonium salt/irondimer=2.1, NCO/OH=1.0, weight % iron dimer=0.5%, iodonium salt=1.2%.Samples were irradiated simultaneously using 366 nm BlakRay bulbs (15watts) for 10 min, then analyzed by 400 MHz ¹ H nuclear magneticresonance spectroscopy. Conversions to polymer are listed in Table XII.Curing agents comprising other combinations of organometallic compoundsand onium salts can be used in place of [CpFe(CO)₂ ]₂ and Ph₂ IPF₆,respectively.

                  TABLE XII                                                       ______________________________________                                        Dual Curing of Polyurethane Precursors and                                    Ethylenically Unsaturated Monomers                                                              Conversion                                                                    to polymer                                                  Onium Salt  Conditions  Acrylate Urethane                                     ______________________________________                                        Ph.sub.2 I.sup.+                                                                          Dark        --        4%                                          Ph.sub.2 I.sup.+                                                                          Irradiation 79%      56%                                          Ph.sub.2 I.sup.+                                                                          Irradiation,                                                                              76%       8%                                                      deoxygenated                                                      None        Dark         0%      11%                                          None        Irradiation 24%      75%                                          None        Irradiation,                                                                              trace    10%                                                      deoxygenated                                                      ______________________________________                                    

EXAMPLE 19

This example demonstrates simultaneous curing of ethylenicallyunsaturated monomers and epoxies. Gelation times will not show that bothmonomers have reacted at the same time. It is possible to use nuclearmagnetic resonance spectroscopy to differentiate the two polymers in thepresence of each other. The experiment was carried out in the followingmanner: A 1/1, w/w, mixture of methyl acrylate/cyclohexene oxide wasprepared. To a 10g sample of this mixture was added 0.01g of [CpFe(CO)₂]₂ or Mn₂ (CO)₁₀ diphenyliodonium hexafluorophosphate (0.024g with theiron dimer, 0.03 g with the manganese dimer) or specified amounts ofboth compounds. In a small vial was placed 2 ml of the sample and it waspurged for 1 min before and continually during irradiation. The lightsource was two 15 watt G.E. blacklite bulbs. Irradiation time was 2minutes. Immediately after completion of the photolysis, the NMR inCDCl₃ was taken. The amount of polymerization was determined by theratio of the peak intensity of the polymer to that of polymer plusmonomer. The results of the study are shown in Table XIII.

                  TABLE XIII                                                      ______________________________________                                        Percent Conversion to Polymer from NMR Study.sup.a                            Curing Agent       Epoxy   Acrylate                                           ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                           .sup.11 0.sup.b                                                                      18                                                 [CpFe(CO).sub.2 ].sub.2 /iodonium                                                                35      60                                                 iodonium           <5      <10                                                Mn.sub.2 (CO).sub.10                                                                              <0.5    <0.5                                              Mn.sub.2 (CO).sub.10 /iodonium                                                                   37      47                                                 ______________________________________                                         .sup.a NMR's taken on a 400 MHz instrument.                                   .sup.b None detected in the NMR.                                         

As can be seen from the NMR results, this system efficiently initiatedboth epoxy and free radical polymerization simultaneously. Curing agentscomprising other combinations of organometallic compounds and oniumsalts can be used in place of [CpFe(CO)₂ ]₂ and Mn₂ (CO)₁₀, and Ph₂IPF₆, respectively.

EXAMPLE 20

This example demonstrates the simultaneous curing of ethylenicallyunsaturated and epoxy monomers in a crosslinkable system. The curablecomposition consists of methyl acrylate, cyclohexene oxide and glycidylacrylate. If only epoxy or acrylate cure are initiated, then this systemwill produce a soluble polymer. Only if both epoxy and acrylate cure areinitiated will a crosslinked insoluble polymer be produced.

All monomers were distilled before use; methyl acrylate and glycidylacrylate from hydroquinone. Sample preparations were carried out undersubdued lights. The polymerizable mixture consisted of 0.2 ggamma-butyrolactone, 1.0 g glycidyl acrylate, 5.0 g methyl acrylate and5.0 g cyclohexene oxide. Depending on the test, added to this were 0.05g of the desired organometallic compound and/or 0.1 g diphenyliodoniumhexafluorophosphate. A 3 g portion of this composition was placed in aglass vial and irradiated between two 15 watt G.E. daylight fluorescentbulbs using an Ultraviolet Products lamp holder (lamp separationdistance 4 cm). The sample was purged with nitrogen for one minutepreceeding and continuously during photolysis. The irradiation timerequired to produce a polymer insoluble in chloroform was recorded, andis noted in Table XIV. Alternatively, these compositions can be curedthermally.

                  TABLE XIV                                                       ______________________________________                                        Simultaneous Photoinitiation of Free Radical and Epoxy                        Cure in a Crosslinkable System                                                              Cure Time.sup.a                                                                 No Onium   Onium Salt                                         Compound        Salt Added Added                                              ______________________________________                                        [CpFe(CO).sub.2 ].sub.2                                                                       >15        1                                                  CpFe(CO).sub.2 SnPh.sub.3                                                                     >15        10                                                 CpFe(CO).sub.2 GePh.sub.3                                                                     >15        15                                                 [CpFe(CO).sub.2 ].sub.2 SnPh.sub.2                                                            >15        10                                                 Mn.sub.2 (CO).sub.10                                                                          >15        1.5                                                (CO).sub.5 MnSnPh.sub.3                                                                       >15        10                                                 [(CO).sub.5 Mn].sub.2 SnPh.sub.2                                                              >10        4                                                  Re.sub.2 (CO).sub.10                                                                          >10        5                                                  [CpMo(CO).sub.3 ].sub.2.sup.b                                                                 >15        1.5                                                CpMo(CO).sub.3 SnPh.sub.3                                                                     >15        10                                                 ______________________________________                                         .sup.a time in minutes to produce insoluble crosslinked system.               Diphenyliodonium hexafluorophosphate alone under these comditions does no     produce a crosslinked system after 15 minutes.                                .sup.b Only 0.01 g of this compound used.                                

Various modifications and alternations of this invention will becomeapparent to those skilled in the art without departing from the scopeand spirit of this invention, and it should be understood that thisinvention is not to be unduly limited to the illustrative embodimentsset forth herein.

We claim:
 1. An energy polymerizable composition comprisinga) least oneethylenically-unsaturated monomer b) at least one epoxy monomerdifferent from the monomer in a) c) a curing agent comprising(1) anorganometallic compound, and (2) an onium salt,wherein saidorganometallic compound has the formula,

    L.sup.1 L.sup.2 L.sup.3 M

wherein L¹ represents none, or 1 to 12 ligands contributing pi-electronsthat can be the same or different ligand selected from substituted andunsubstituted acyclic and cyclic unsaturated compounds and groups andsubstituted and unsubstituted carbocyclic aromatic and heterocyclicaromatic compounds, each capable of contributing 2 to 24 pi-electrons tothe valence shell of M; L² represents none, or 1 to 24 ligands that canbe the same or different contributing an even number of sigma-electronsselected from mono-, di-, and tri-dentate ligands, each donating 2, 4,or 6 sigma-electrons to the valence shell of M; L³ represents none, or 1to 12 ligands that can be the same or different, each contributing nomore than one sigma-electron each to the valence shell of each M;Ligands L¹, L², and L³ can be bridging or non-bridging ligands; Mrepresents 1 to 4 of the same or different metal atoms selected from theelements of Periodic Groups IVB, VB, VIB, VIIB, and VIII; with theproviso that said organometallic compound contains at least one of ametal-metal sigma bond and L³ ; and with the proviso that L¹, L², L³,and M are chosen so as to achieve a stable configuration.
 2. Thecomposition according to claim 1 wherein said onium salt has the formulaII

    AX                                                         II

wherein A is an iodonium on sulfonium cation, and X is an organicsulfonate counterion, or a halogenated metal or metalloid counterion. 3.The composition according to claim 1 wherein the ratio ofethylenically-unsaturated monomer to said epoxy compound is in the rangeof 99:1 to 1:99.
 4. The composition according to claim 1 wherein saidcuring agent is present in the range of 0.1 to 20 weight percent of thetotal composition.
 5. The composition according to claim 4 wherein saidcuring agent is present in the range of 0.1 to 10 weight percent of saidtotal composition.
 6. The composition according to claim 1 wherein theratio of organometallic compound to onium salt of said curing agent isin the range of 10:1 to 1:10 by weight.
 7. The composition according toclaim 6 wherein the ratio of organometallic compound to onium salt is inthe range of 5:1 to 1:5 by weight.
 8. The composition according to claim1 wherein said ethylenically-unsaturated monomer is selected from thegroup consisting of acrylates, acrylamides and vinyl compounds.
 9. Thecomposition according to claim 8 wherein said ethylenically-unsaturatedmonomer is an acrylate.
 10. The composition according to claim 1 whereinsaid epoxy compound is a 1,2-epoxide.
 11. The composition according toclaim 1 wherein said organometallic compound is selected from the groupconsisting of [CpFe(CO)₂ ]₂, Mn₂ (CO)₁₀, CpPt(CH₃)₃.
 12. The compositionaccording to claim 1 wherein said organometallic compound is Mn₂ (CO)₈(1,10-phenanthrolin).
 13. The composition according to claim 1 whereinsaid onium salt is at least one of Ph₂ I⁺ PF₆ ⁻, Ph₂ I⁺ SbF₆ ⁻, Ph₂ I⁺AsF₆ ⁻, Ph₂ I⁺ SbF₅ (OH)⁻, Ph₃ S⁺ PF₆ ⁻, Ph₃ S^(+SbF) ₆ ⁻, Ph₃ S⁺ AsF₆⁻, PhSC₆ H₄ SPh₂ SbF₆, and Ph₃ S⁺ SbF₅ (OH)-, wherein Ph is phenyl. 14.A layered structure comprising a substrate having coated on one surfacethereof the polymerizable composition according to claim
 2. 15. Thecured structure according to claim
 14. 16. The layered structureaccording to claim 14 which is an imageable structure.
 17. An energypolymerizable composition comprisinga) at least oneethylenically-unsaturated monomer b) at least one epoxy monomerdifferent from the monomer in a) c) a curing agent comprising(1) anorganometallic compound, and (2) an onium salt, wherein saidorganometallic compound has the formula,

    L.sup.1 L.sup.2 L.sup.3 M

wherein L¹ represents none, or 1 to 12 ligands contributing pi-electronsthat can be the same or different ligand selected from substituted andunsubstituted acyclic and cyclic unsaturated compounds and groups andsubstituted and unsubstituted carbocyclic aromatic and heterocyclicaromatic compounds, each capable of contributing 2 to 24 pi-electrons tothe valence shell of M; L² represents none, or 1 to 24 ligands that canbe the same or different contributing an even number of sigma-electronsselected from mono-, di-, and tri-dentate ligands, each donating 2, 4,or 6 sigma-electrons to the valence shell of M; L³ represents none, or 1to 12 ligands that can be the same or different, each contributing nomore than one sigma-electron each to the valence shell of each M;Ligands L¹, L², and L³ can be bridging or non-bridging ligands; Mrepresents 1 to 4 of the same or different metal atoms selected from theelements of Periodic Group VIII; with the proviso that saidorganometallic compound contains at least one of a metal-metal sigmabond and L³ ; and with the proviso that L¹, L², L³, and M are chosen soas to achieve a stable configuration.
 18. A process comprising the stepsof:a) providing a polymerizable mixture comprising(1) at least oneethylenically-unsaturated compound, and (2) at least one epoxy monomer,and (3) a catalytically effective amount of a curing agent comprising(a) an organometallic compound having the formula,

    L.sup.1 L.sup.2 L.sup.3 M

wherein L¹ represents none, or 1 to 12 ligands contributing pi-electronsthat can be the same or different ligand selected from substituted andunsubstituted acyclic and cyclic unsaturated compounds and groups andsubstituted and unsubstituted carbocyclic aromatic and heterocyclicaromatic compounds, each capable of contributing 2 to 24 pi-electrons tothe valence shell of M; L² represents none, or 1 to 24 ligands that canbe the same or different contributing an even number of sigma-electronsselected from mono-, di-, and tri-dentate ligands, each donating 2, 4,or 6 sigma-electrons to the valence shell of M; L³ represents none, or 1to 12 ligands that can be the same or different, each contributing nomore than one sigma-electron each to the valence shell of each M;Ligands L¹, L², and L³ can be bridging or non-bridging ligands; Mrepresents 1 to 4 of the same or different metal atoms selected from theelements of Periodic Groups IVB, VB, VIB, VIIB, and VIII;with theproviso that said organometallic compound contains at least one of ametal-metal sigma bond and L³ ; and with the proviso that L¹, L², L³,and M are chosen so as to achieve a stable configuration; and (b) anonium salt; b) allowing said mixture to polymerize or adding energy tosaid mixture to effect polymerization.
 19. The method according to claim18 wherein said energy is at least one of electromagnetic radiation,accelerated particles, or thermal energy.
 20. The method according toclaim 18 wherein said polymerizable mixture further comprises up to 90weight percent of a solvent based on the total mixture.
 21. A curedcomposition prepared according to the method of claim
 18. 22. A shapedarticle according to claim 21.